1. Field of the Invention
The present invention relates to a method of repairing electrode pattern defects, and more particularly, to a method of repairing electrode pattern defects with a conductive paste and a laser beam.
2. Description of the Prior Art
As the requirements and applications of flat panel displays grow, the plasma display panel (PDP) gains more and more potential because of its small size, large display area, and wide view angle.
The plasma display panel substantially comprises a front substrate, a back substrate, a discharge gas filled between the front substrate and the back substrate for generating ultraviolet lights, and a plurality of parallel sustain electrodes positioned on the surface of the front substrate for discharging electricity. The front substrate further comprises a plurality of bus electrodes respectively connected to each sustain electrode. The back substrate further comprises a plurality of address electrodes vertical to the sustain electrodes, a plurality of ribs parallel to the address electrodes, and a fluorescent layer coated on the address electrodes and the ribs. Each two neighboring ribs and two corresponding sustain electrodes thereon form a discharge cell for generating lights.
Generally speaking, the plasma display panel includes hundred thousands of discharge cells, and each discharge cell is hundreds of micrometers in length. While an initial voltage is applied to the sustain electrodes, the discharge gas located between the front substrate and the back substrate will be discharged to generate ultraviolet lights. Then while the ultraviolet light irradiates different fluorescent layers, the discharge cells will generate red, green, or blue light for displaying different colors.
It is evident that the sustain electrodes are critical to the plasma display panel. The plasma display panel will function well only when the sustain electrodes discharge normally. However, the sustain electrode defects occur from time to time during the manufacturing process. In addition, a high initial voltage of the sustain electrode would increase the operational temperature of the plasma panel display. Therefore more and more electrode pattern designs are proposed to reduce the initial voltage of the sustain electrode. As the complexity of the electrode pattern increases, electrode pattern defects will occur more easily than before.
Take the sustain electrode for example. While forming the sustain electrode, a transparent conductive layer, such as ITO or IZO, is first formed on the surface of the front substrate by a sputtering process, then the electrode pattern is defined by a photo-etching process. Since the complexity of the electrode increases as the critical dimension decreases, the electrode pattern defects will easily occur due to particles or scratches of the photo mask.
The electrode pattern defects would affect the discharge efficiency, and further deteriorate the display quality of the plasma display panel. However, since a related solution regarding this problem does not exist, most manufacturers adopt looser standards in order to increase throughput. Even so, the throughput of plasma display panel is not high enough. Therefore, how to solve the electrode pattern defects is a major topic for study.